(1) Field of the Invention
The present invention relates to earth boring machines and methods for boring large diameter vertical blind shafts through medium and hard rock formations. A typical use of the present shaft boring machine is to construct a vertical mine shaft. The invention fills a long-felt need and brings the advantages of machine rock boring to blind shaft construction. These advantages are basically: higher advance rates; an accurate, smooth bore which facilitates shaft equipping and significantly cuts concreting costs; reduced manpower; and, safer working conditions. The higher advance rates of the present shaft boring machine in the sinking of the shaft can be accomplished because the machine can operate on a continuous basis rather than in cycles as in the conventional drill-and-blast method of blind shaft sinking. It is intended that the machine will be used in conjunction with appropriate auxiliary service stages and hoisting systems to allow the installation of primary and secondary lining, ventilation, and other required services as the machine advances. Such auxiliary equipment is not included in the scope of the invention.
(2) Description of the Prior Art
The prior art includes the following machines:
Wick U.S. Pat. No. 2,221,226 discloses in FIG. 1 a large diameter shaft sinking and excavating machine having a non-rotary cylindrical caisson 3 extending upwardly from a shoe blade 4. The rotary frame 8 supported in the lower end of the caisson rotates about the vertical centerline and has shovels 19 which push the earth toward the center of the machine. The rotary frame 8 also carries plows 20 as shown in FIG. 5 which dig up the earth. Conveyor 30 lifts the earth vertically in scoops 41 and at the upper sprocket 34 the earth is thrown into the swingable spout 53 which directs the earth into a first bucket 49 as shown in FIG. 2. When the first bucket is full, it is lifted by a hoisting unit located at the surface. Raising the full bucket 49 tips the spout 53 towards the empty bucket. The buckets 49 travel in channeled tracks 42.
Harrison U.S. Pat. No. 2,587,844 discloses a cage and operating mechanism for a shaft shovel 111. A hoist 100 is connected to the cable 106 which passes over the pulley 99 on the hinged pulley boom 98 and extends downwardly to operate the shovel 111. A second hoist 103 is mounted on the plate 104. The second hoist 103 is connected to the crowding mechanism of the dipper stick 109 by the cable 107. The hoist 103 actuates the dipper stick 109 while the hoist 100 raises and lowers the shovel 111 which in turn is secured to the end of the dipper stick 109. The dipper stick 109 may be either advanced or retarded with respect to the swinging boom 97 by means of the hoist 103. The tub 114 has a cable 115 connected thereto which extends up to the top of the shaft so that the tub 114 may be raised or lowered by suitable surface equipment. A cord 116 is connected to the latch 117 on the back of the shovel 111 and the cord 116 extends upward to the operator's cage. In operation, the operator commences the excavation by retarding or advancing the position of the dipper stick and at the same time raising the shovel so as to break up rock and aggregate. The shovel 111 is moved to a position directly above the tub 114 and then the shovel is tripped by means of the cord 116 which is connected to the latch 119. The tub may then be raised to the surface to permit disposal of the rock and aggregate and then the operation is repeated until the excavation of the vertical shaft has been completed.
Zeni U.S. Pat. No. 2,769,614 discloses in FIG. 6 a shaft sinking machine including a circular plate 10 providing an operating head with a cylindrical casing 11 extended downwardly from its peripheral edge and having toothed rotary cutters 12 journaled on the lower edge thereof, a motor platform 13 which is stationary and which is provided with a peripheral flange 14 from which the head 10 is suspended with spaced clips 15 which are U-shaped in cross section, a pump platform 16 spaced above the motor platform 13 by struts 18, a horizontally disposed screen 19 positioned above the disk 17, an anti-torque vise including threaded studs 20 mounted in sleeves 21 and actuated by nuts 22 to adjust the machine in relation to the shaft, hydraulic cylinders 23 mounted on the motor platform 13 and pivotally connected to toggle acting levers 24, a plurality of motors 25, a vacuum pump 26 and a hydraulic pump 27. In operation, compressed air is forced downwardly from a conventional compressor or from the pressure side of the vacuum pump 26 through a tube 43 to a head 44 from which the air is distributed by ducts 45 to nozzles 46 which are adjacent to the toothed rotary cutters 12. The cuttings from the cutters and drags 6 positioned between the cutters are drawn upwardly by the vacuum from the pump 26 through ducts 47 which extend upwardly through the partition 41 and into the open area 42 where the cuttings, as indicated by the numeral 48, are deposited upon the upper surface of the partition 41. The ducts 47 are provided with collecting nozzles as indicated by the numeral 49. From the open area 42, the air is drawn through the tube 72 to the suction side of the vacuum pump 26.
Ikeda U.S. Pat. No. 3,770,067 discloses in FIG. 2 a reaction counterbalanced earth boring machine 1 intended to be used underwater. The machine 1 has a body 100 including a central member 110, a transmission gear box 130 secured to the central member 110, and submersible electric motors 120 mounted on the gear box 130. The central member 110 is a double pipe construction including an inner pipe 111 and an outer pipe 112 which are connected with the water exhaust hose 5 and the water supply hose 4. The water supplied under pressure through the water supply hose 4 is passed between the inner pipe 111 and the outer pipe 112 and discharged from nozzles 141. The inner pipe 111 is connected at an intermediate point to the air supply hose 6 which supplies compressed air for exhausting slime through the water exhaust hose 5. The pressurized water is discharged to the bottom of the hole which is being bored by cutters 160. The water carries the slime produced during the boring operation up through the inner pipe 111 for discharge from the hole. Thus, the machine maintains a reverse water circulation. As shown in FIG. 3, each of the cutters 160 is rotated clockwise about its own axis as shown by the arrow P while revolving about the axis of the machine in the counterclockwise direction as shown by the arrow Q. Thus, the rotating torque acting on the cutters is counterbalanced by the revolving torque.
Sourice U.S. Pat. No. 3,894,587 discloses a machine for drilling in hard rock formations comprising a frame 1 which is in the form of a box section furnished at its upper end with rings 2 which enable it to be suspended from suspension members 3. The frame 1 is also furnished with guide plates 4 having angled edges which cooperate with the walls of the hole 5 which the machine is excavating. At the lower face of the frame 1, there are plate-like supports 6 which carry a hydraulic or electric motor 7 having a variable speed. The motors rotate in opposite directions in order to cancel out the resulting reaction forces. The shafts 9 of the motors 7 carry drums 11 which extend from the support 6 to the plane of the guide plate 4. Each of the drums 11 is fitted with peripheral helical threads 12 carrying tools 13, such as teeth or small rollers. The helical threads 12 are symmetrically arranged relative to the support 6 and are of opposing pitch so that when the drums revolve in the direction shown in FIG. 1, the excavated materials are brought towards the center of the device so that they can be removed through a central duct 14 mounted on frame 1. In operation, mud is poured into the excavation for the purpose of filling the excavation and preventing the walls from falling in. The mud is continuously removed by the duct 14 together with the excavated material by inverse circulation.
Sugden U.S. Pat. No. 3,965,995, assigned to The Robbins Company, discloses a machine 10 for boring a large diameter blind hole consisting of a cutter wheel 60 mounted at the lower end of the machine for rotation about a horizontal tubular support 58. The cuttings are picked up by buckets 74 on the cutter wheel 60 and are directed into the tubular support 58 to be received by an endless bucket conveyor 78 which carries them upwardly to a discharge station. As the machine is advanced, the cutter wheel 60 is rotated to make a first cut in the shape of the leading portion of the cutter wheel. The cutter wheel is then retracted from the cut and is rotated about the axis of the hole. This positions the cutter wheel so that when it is advanced again it will make a second cut which crosses the first. This procedure is repeated until the desired cross-sectional configuration of the hole is obtained. The cuttings of earth material are raised upwardly and are discharged into first one and then the other of the lift buckets 32 and 34. In FIG. 1, bucket 32 is shown receiving cuttings and the bucket 34 is shown in an elevated position with the cuttings from it being discharged into the hopper 52. A similar hopper 54 is provided for bucket 32 on the opposite side of the tower 30. Hoppers 52 and 54 serve to accumulate the cuttings and periodically discharge them into a truck or other transporting means provided for carrying them away from the work site.
Dubois U.S. Pat. No. 3,995,907 discloses an underground excavating machine having independently movable half-frames The machine includes two half-frames vertically arranged side-by-side, with two parallel vertical shafts supported by the two half-frames. A separate turret is pivotally supported around each of the shafts, each turret having a cutting head which can rotate about a horizontal axis and which is equipped with tools for excavating. The two half-frames are slidably movable horizontally in relation to one another, with a control member connected between the two half-frames for controlling the relative movement, the two half-frames being selectively positionable on the gallery floor by the relative movement, one half-frame being movable while the other half-frame remains fixed in position.
Cunningham U.S. Pat. No. 4,102,415 discloses an earth drilling machine including a main body tube with jacks to releasably support it within a drilled shaft or within an erected startup shaft. An outer casing is rotatably mounted within the main body tube, and carries a horizontal base on which are driven wheels and vertical shafts which have cutting elements. Means within the casing for fluid input and evacuation within the drill area is provided to form a slurry of the fluid and the excavated material for withdrawal through the casing. As the drilling continues, the main body tube is lowered into the shaft. The cutting elements include plates with cutting edges mounted on individual axles so that the edges are maintained in cutting relation to the area to be drilled.
Paurat et al U.S. Pat. No. 4,274,675 discloses a shaft-sinking apparatus with a milling head and a central worm conveyor. The machine platform can be anchored against the wall of the shaft and carries an orbiting tool for cutting away the floor of the shaft, thereby dumping the cuttings into a pilot-bore hole continuously drilled by a pilot-bore unit. The pilot-bore unit has a head for advancing the pilot bore and is provided with a worm conveyor running centrally through the shaft to transfer the cuttings to a bucket on a loading platform disposed above the main platforms. The platforms have cylinder arrangements whereby they are independently anchored to the vertical wall of the shaft.
Paurat et al U.K. Patent Application GB No. 2,111,561A discloses a machine for sinking mine shafts consisting of a cross beam 1 adapted to be disposed in a shaft SW, a cutter attached thereto for excavating the shaft floor SO, a vertical conveyor 3, and a transfer attachment 4 to transfer the excavated material to the vertical conveyor. The cutter has a milling and conveying worm 2 to swivel about the shaft axis 5 and feed the excavated material to the axis of the shaft. The cross beam 1 is equipped with bracing shoes 6 which can be extended or retracted to fix the position of the cross beam. The milling and conveying worm 2 and the cross beam 1 are movable relative one to the other by means of a cylinder-piston unit 8 disposed between the cross beam 1 and the conveying worm 2. The vertical conveyor 3 is formed by a belt conveyor which is deflected from the vertical into the horizontal and is formed into a tubular conveyor 9 in the vertical run and a trough 10 in the horizontal run where it functions as the input section of the transfer attachment. The machine is used in an operating cycle whereby the milling and conveying worm 2 and the cross beam 1 move relative one to the other with rhythmic forward and backward movements, thereby excavating the shaft floor SO.